Carel MPXone

Compact controller for showcases and cold rooms with an optional expansion valve driver and a main/secondary network of up to nine units (five on the Basic model). Codes are close to MPXPRO, with some differences in probe numbering.

What it is: Display case and cold room controller. Basic and Medium/Advanced versions. Successor to MPXPRO with Bluetooth and the APPLICA app.

Key combo: Hold PRG for 3 s, then enter the service password, to reach the parameter menus. Press ALARM briefly to view alarms; hold it 3 s to reset.

Error codes ↓
Enter service mode ↓
Change a setting ↓

Carel MPXone error codes

Code	Meaning	Likely cause	How to reset
rE	Control probe fault	The probe used for control has failed or is not configured	Automatic. Cooling runs on the duty-cycle setting (c4) meanwhile.
E1	Probe S1 fault	Probe open, shorted, unplugged or wrong probe type set	Automatic once the probe reads normally. Check wiring and the probe-type parameters.
E2	Probe S2 fault	Probe open, shorted, unplugged or wrong probe type set	Automatic once the probe reads normally. Check wiring and the probe-type parameters.
E3	Probe S3 fault	Probe open, shorted, unplugged or wrong probe type set	Automatic once the probe reads normally. Check wiring and the probe-type parameters.
E4	Probe S4 fault	Probe open, shorted, unplugged or wrong probe type set	Automatic once the probe reads normally. Check wiring and the probe-type parameters.
E5	Probe S5 fault	Probe open, shorted, unplugged or wrong probe type set	Automatic once the probe reads normally. Check wiring and the probe-type parameters.
E6	Probe S6 fault	Probe open, shorted, unplugged or wrong probe type set	Automatic once the probe reads normally. Check wiring and the probe-type parameters.
E11–E14	Serial probe S11 to S14 not updated	Value sent over the network has stopped updating	Automatic. Check the network and the unit sending the value.
LO	Low temperature alarm	Alarm probe below the AL threshold for longer than Ad	Resets by itself once the cause clears.
HI	High temperature alarm	Alarm probe above the AH threshold for longer than Ad	Resets by itself once the cause clears.
LO2	Second low temperature alarm	Below the AL2 threshold (probe set by AA2)	Resets by itself once the cause clears.
HI2	Second high temperature alarm	Above the AH2 threshold (probe set by AA2)	Resets by itself once the cause clears.
IA	Immediate external alarm	Digital input set as immediate alarm has opened	Automatic. Cooling runs on duty setting A6.
dA	Delayed external alarm	Digital input set as delayed alarm stayed open past A7	Automatic. Cooling runs on duty setting A6 if A7 is not 0.
dor	Door open too long	Door switch open past the door alarm delay	Resets by itself once the cause clears.
Etc	Real time clock fault	Clock not set or failed	Set the clock; replace the controller if it returns.
LSH	Low superheat	Expansion valve overfeeding (EEV models)	Automatic. Check superheat set point, probes and valve.
LSA	Low suction temperature	Suction temperature below its threshold too long (EEV models)	Automatic or manual depending on setting.
MOP	Maximum operating pressure	Evaporating pressure too high (EEV models)	Automatic.
LOP	Low evaporating temperature	Evaporating temperature too low (EEV models)	Automatic.
bLo	Valve blocked	Electronic valve appears stuck (EEV models)	Manual reset; disabled when P14 = 0.
Edc	Stepper driver communication error	Lost contact with the valve driver	Automatic. Check driver wiring.
HA	HACCP alarm type HA	High temperature during normal running for longer than the HACCP delay	Manual. Read and reset in the HACCP menu.
HF	HACCP alarm type HF	High temperature after a power cut	Manual. Read and reset in the HACCP menu.
MA	Lost contact with main controller (on a secondary)	Network cable or address problem	Automatic once communication returns.
u1…	Lost contact with secondary unit 1, 2, 3… (on the main)	Network cable or address problem	Automatic once communication returns.
n1…	Alarm on network unit 1, 2, 3…	A unit in the network has its own alarm	Check the unit named.
GPE	Custom gas parameter error	Custom refrigerant settings invalid	Automatic once corrected.
dA1 / dA2	EVD ice or mini driver: probe S1 / S2 fault	Probe on the separate valve driver failed	Automatic once fixed.
AFr	EVD ice or mini driver firmware too old	Driver firmware below 1.7	Clears once compatible firmware is recognised.
GHI / GLO	Generic function above maximum / below minimum	A user-set generic monitor tripped	Automatic.

How to enter service / parameter mode

Hold PRG for 3 seconds.
Enter the service password with UP / DOWN and press PRG to confirm.
Choose a category (VIS, CtL, CMP, DEF, ALM, FAN, EVD, RTC…) and press PRG.
Scroll to the parameter you need.

How to change and save a setting

With the parameter showing, press PRG to display its value.
Change it with UP or DOWN.
Press PRG to save and return to the code.
Hold PRG for 3 s to go back a level.

Other useful key presses

Task	How
View alarms	Press ALARM briefly, then UP / DOWN to scroll.
Reset alarms	Hold ALARM for 3 s.
First start-up	A set-up wizard asks for refrigerant type (PH) and basic settings; press PRG at the end.

Notes

A permanent Err on the display points to a faulty display or controller.
The Basic model is limited to five network units, so only u1–u5 and n1–n5 apply.

For licensed technicians only. This equipment can involve mains voltage, high-voltage microwave circuits, gas and refrigerant. Isolate power (and gas) before opening panels, follow the manufacturer's manual and your local licensing rules (for example ARC refrigerant handling and electrical or gas licences). Wrong settings can spoil food or damage equipment. Check every value on the unit in front of you before changing it.

Based on: Carel MPXone user manual (+0300086EN rel. 2.1) and MPXone instruction sheet (+0500140EN). Always check the manual for your exact model and software version.

ServiceModes is not affiliated with Carel or any other manufacturer. Written in our own words from the manufacturer's documentation.